Anecdotal "evidence" here -- my 10gal RCS tank has been neglected for probably a year -- I may drop an algae wafer in there once a week, and I never bother with water changes - only top off once the water level is nearing halfway down the tank. No filtration either, just a heater, airstone, and a ton of java moss getting spill over light from another tank.
About a month ago, I started doing weekly water changes. When I showed my RCS to a buddy last night, I just realized how "deep" and "solid" red my RCS are now. They were pale last month, when I compare from memory. I have also spotted quite a lot of tiny little shrimplets now, whereas I didn't find a single one last month.
I'd listen to the more experienced invert-keeping members here, but for my 10gal RCS tank, I'll continue doing my weekly 2.5gal water change. Including wiping any water spills, it takes what, 5 minutes?